Cytochrome P450terp is a class I (mitochondrial/bacterial) P450 that catalyzes the hydroxylation of alpha-terpineol as part of the catabolic assimilation of this compound by a pseudomonad species. Crystals grown from the purified protein have the symmetry of space group P6(1)22, and cell dimensions a = b = 69 ...
Cytochrome P450terp is a class I (mitochondrial/bacterial) P450 that catalyzes the hydroxylation of alpha-terpineol as part of the catabolic assimilation of this compound by a pseudomonad species. Crystals grown from the purified protein have the symmetry of space group P6(1)22, and cell dimensions a = b = 69.4 A, c = 456.6 A, alpha = beta = 90 degrees, gamma = 120 degrees. Diffraction data were collected at the Cornell High Energy Synchrotron Source, and the structure of P450terp was solved by a combination of molecular replacement and multiple isomorphous replacement techniques. A model of P450terp was built and refined against native data, to an R-factor of 18.9% for data with I > or = sigma(I) between 6.0 A and 2.3 A resolution. This model contains 412 of the 428 P450terp amino acid residues; the loop between helices F and G is disordered in the crystal. While the overall fold of P450terp is very similar to that of P450cam, only three-quarters of the C alpha positions can be superimposed, to a root-mean-square deviation of only 1.87 A. The mode of substrate binding by P450terp can be predicted, and probable substrate contact residues identified. The heme environment and side-chain positions in the adjacent I-helix suggest possible modes of proton delivery in the catalytic cycle of the enzyme.
Related Citations:
Crystallization and Preliminary X-Ray Diffraction Analysis of P450-Terp and the Hemoprotein Domain of P450-Bm-3, Enzymes Belonging to Two Distinct Classes of the Cytochrome P450 Superfamily Boddupalli, S.S., Hasemann, C.A., Ravichandran, K.G., Lu, J.-Y., Goldsmith, E.J., Deisenhofer, J., Peterson, J.A. (1992) Proc Natl Acad Sci U S A 89: 5567
Cytochrome P450-Terp: Isolation and Purification of the Protein and Cloning and Sequencing of its Operon Peterson, J.A., Lu, J.-Y., Geisselsoder, J., Graham-Lorence, S., Carmona, C., Witney, F., Lorence, M.C. (1992) J Biol Chem 267: 14193
Organizational Affiliation:
Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas 75235-9050.
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